Part of the problem is that 20 percent of the 1.2 million Americans infected with HIV don’t know they’re infected. That’s 240,000 people walking around undiagnosed.

If HIV-infected people are getting good medical care, the virus can be brought under control about 80 percent of the time. A Reuters report on the study says that suppressing the virus through treatment reduces the chance of transmission to a partner by a whopping 96 percent.

But if you’re not diagnosed you can’t get treated, plus there are other problems including people dropping treatment for financial and other reasons, CBS/AP says. CDC director Dr. Thomas Frieden told Reuters that “the major area of need in the United States is in "strengthening the cascade" of care by improving access and making sure people continue taking their medication to ensure the virus in their body is kept low enough to prevent the spread of the infection.”

The CDC report “follows new global AIDS priorities set by U.S. Secretary of State Hillary Clinton focused on HIV-fighting drugs as a way of preventing new infections that could bring the goal of “an AIDS-free generation within reach,” Reuters reports.